Another Carb Question

[GeorgiaSnake]

I can pick up a new Holley 4150 HP (80529-1,or any other Holley carb) for almost nothing or spend a good bit more and get a Demon. I would put either on top of the following.

351 W
Scat 3.850 Stroker
Ford D6OE Rods - ARP Bolts
Engine Tech - Hypereutectic Pistons 9.8:1
Hasting Molly Rings
Elgin E961P - Solid Lifter Cam Int .512 Exh. .536
Ported & Polished Edelbrock Performer RPM Heads
Port Matched Edelbrock Performer Intake
Port Matched 1 1/2" Headers 1 5/8" per Tony (the polisher)
Holly 3310 - 750 CFM
Roller Rockers
MSD & Modified Centrifical Advance Electronic Distributor

Any input from the group would be appreciated.

Randy

[DAVID GAGNARD]

Randy;


I had been riding around since 1996 with a 600 vac. sec. Holley on my 351-W,a couple of trips to the drag strip a year and the rest is street driving with most of that on the highway.... Very pleased with the performance and gas mileage and driveability.....

Started road racing this year,went three times,a buddy gave me a well used 15 year old Holley 600 dp to try. I put a kit in it and re-jetted it for my car and put it on.... Difference to me is like night and day.... Comes off the line like a bat outa hell and pulls hard thru the rpm range,great for road racing,probably not good for gas mileage..... I really find no difference in street driving with it and have not had a chance to check gas mileage yet... This weekend I'm supposed to go to a Mustang and Ford car show about 160 or so miles away(one way)and I definetly plan to check my gas mileage to compare the two carbs....

If you are street driving and interested in gas mileage stay with what you have,if you do a little racing go with the Holley dp,the Demon may not be worth the extra money if you do not use it like it was meant to be used (racing)...

Just my .02 cents.....

David

[Tony Radford]

Yo Randy, I think your headers are 1 5/8" tubes. Maurice told me he puts those on all of Bill's engines. I measured mine and sure enough, that's what I'm running. Not 1 1/2. In any event, I think the Demon carb is about $250 or so over the Holley. My Mighty Demon lists for $500. Didn't Barry Grant suggest a Speed Demon? That's what they recommended to Clyde (who was also threatening to replace his Holley with a BG). Bill stuck the biggest cam he could shove into my motor without having to flycut the pistons. I think it's the cam and that big Vic. Jr. intake that pushed me over into the Mighty Demon category. If you go down there, you can look at mine still in the box. It's a nice piece of equipment. In any event, I'm glad I went with the Demon and that it has mechanical secondaries. I want a screamer!

[Jack21]

Similar setup.

Replaced Holley #4778 700DP with Speed Demon 650DP. Difference is night and day, and all carb gremlins gone.

Don't think you need to spring for the mighty Demon, but the 750DP Speed Demon would do nicely on your motor. You'll spend more time driving it, and less time tinkering with it as you would a Holley.

[Hal Copple]

i suspect that some engines really do better with one carb or the other, even with similar flow numbers. I have been very happy with my 750 HP vac secondary on my stroked windsor, i was equally happy with the former vac secondary 750 with the choke.

All i can say is that for my engine, my set up runs as well as any fuel injected car does, and i have not had to anything other than wipe it down occasionally in the past year or so, and many miles. I would be confused by too many Demon choices, while the Holley choices seem to me to be much simpler. Probably the most common fault with any of them is going too big for the purpose of the motor.

The guy at my local speedshop say smuch of the difference in carbs is in the metering blocks, anyway.